Open Access
CC BY-NC-ND 4.0 · Eur J Dent 2015; 09(04): 513-517
DOI: 10.4103/1305-7456.172626
Original Article
Dental Investigation Society

Effect of dry cryogenic treatment on Vickers hardness and wear resistance of new martensitic shape memory nickel-titanium alloy

Thilla Sekar Vinothkumar
1   Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences of Sri Ramachandra University, Chennai, Tamil Nadu, India
,
Deivanayagam Kandaswamy
1   Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences of Sri Ramachandra University, Chennai, Tamil Nadu, India
,
Gopalakrishnan Prabhakaran
2   Department of Mechanical Engineering, Velammal Engineering College, Chennai, Tamil Nadu, India
,
Arunachalam Rajadurai
3   Department of Production Technology, MIT Campus, Anna University, Chennai, Tamil Nadu, India
› Author Affiliations
Further Information

Publication History

Publication Date:
23 September 2019 (online)

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ABSTRACT

Objectives: The aim of this study is to investigate the role of dry cryogenic treatment (CT) temperature and time on the Vickers hardness and wear resistance of new martensitic shape memory (SM) nickel-titanium (NiTi) alloy. The null hypothesis tested was that there is no difference in Vickers hardness and wear resistance between SM NiTi alloys following CT under two soaking temperatures and times. Materials and Methods: The composition and the phase transformation behavior of the alloy were examined by X-ray energy dispersive spectroscopy and differential scanning calorimetry, respectively. Fifteen cylindrical specimens and 50 sheet specimens were subjected to different CT conditions: Deep cryogenic treatment (DCT) 24 group: −185°C, 24 h; DCT six group: −185°C, 6 h; shallow cryogenic treatment (SCT) 24 group: −80°C, 24 h; SCT six group: −80°C, 6 h; and control group. Wear resistance was assessed from weight loss before and after reciprocatory wet sliding wear. Results: The as-received SM NiTi alloy contained 50.8 wt% nickel and possessed austenite finish temperature (Af) of 45.76°C. Reduction in Vickers hardness of specimens in DCT 24 group was highly significant (P < 0.01; Tukey's honest significant difference [HSD]). The weight loss was significantly higher in DCT 24 group (P < 0.05; Tukey's HSD). Conclusion: Deep dry CT with 24 h soaking period significantly reduces the hardness and wear resistance of SM NiTi alloy.